Nokia Solutions and Networks (NSN) has reportedly carried out a successful demonstration of what it claims is the world’s first Time Division Duplex-Frequency Division Duplex (TDD-FDD) carrier aggregation in partnership with South Korean operators KT Corp and SK Telecom (SKT). According to a press release issued by the vendor the demonstration was carried out separately with the two cellcos, using NSN’s Flexi Multiradio 10 Base Station.

Pointing to the benefits that could be offered by the technology development, NSN noted that, with carrier aggregation allowing operators to combine their low-frequency FDD bands with high-frequency TDD bands, it could enable cellcos to offer high speed mobile broadband across wider areas. While high-frequency bands are typically uplink limited and have less coverage, NSN noted, in the case of TDD-FDD carrier aggregation operators can improve their high-frequency band TD-LTE coverage by between 50% and 100% using TDD for downlink only and using the lower-frequency FDD for uplink as well as downlink.

Commenting on the technology breakthrough, Jin-hyo Park, senior vice president, head of network technology R&D centre at SK Telecom, noted: ‘The significance of TDD-FDD carrier aggregation is that it provides the technical basis for faster and more efficient data services, combining TD-LTE technology which is becoming more and more widely adopted with FDD-LTE used in most networks today.’ Meanwhile, Qi Zhang, vice president of TD-LTE at NSN, said: ‘It gives us immense satisfaction to achieve the world’s first TDD-FDD carrier aggregation, and we are actively pursuing the 3GPP standardisation of the technology … We have been working hard with the leading Korean operators, KT and SKT, and this demonstration is yet further proof of our thought leadership in the commercialisation of LTE technology for wider adoption.’